Current Issue : July - September Volume : 2017 Issue Number : 3 Articles : 6 Articles
As an unconventional energy, coalbed methane (CBM) mainly exists in coal bed with adsorption, whose productivity is different\nfromconventional gas reservoir. This paper explains the wellbore pressure drop, surface pipeline network simulation, and reservoir\ncalculation model of CBM. A coupled surface/wellbore/reservoir calculation architecture was presented, to coordinate the gas\nproduction in each calculation period until the balance of surface/wellbore/reservoir. This coupled calculation method was applied\nto a CBM field for predicting production. The daily gas production increased year by year at the first time and then decreased\ngradually after several years, while the daily water production was reduced all the time with the successive decline of the formation\npressure. The production of gas and water in each well is almost the same when the structure is a star.When system structure is a\ndendritic surface system, the daily gas production ranked highest at the well which is the nearest to the surface system collection\npoint and lowest at the well which is the farthest to the surface system collection point. This coupled calculation method could be\nused to predict the water production, gas production, and formation pressure of a CBM field during a period of time....
We report a laboratory scale combined absorption and adsorption chemical process to remove contaminants from anaerobically\nproduced biogas using cafeteria (food), vegetable, fruit, and cattle manure wastes. Iron oxide (Fe2O3), zero valent iron (Feo), and\niron chloride (FeCl2) react with hydrogen sulfide (H2S) to deposit colloidal sulfur. Silica gel, sodiumsulfate (Na2SO4), and calcium\noxide (CaO) reduce the water vapour (H2O) and carbon dioxide (CO2). It is possible to upgrade methane (CH4) above 95% in\nbiogas using chemical or physical absorption or adsorption process. The removal efficiency of CO2, H2S, and H2O depends on the\nmass of removing agent and system pH. The results showed that Ca(OH)2 solutions are capable of reducing CO2 below 6%. The\nH2S concentration was reduced to 89%, 90%, 86%, 85%, and 96% for treating with 10 g of FeCl2, Feo (with pH), Fe2O3, Feo, and\nactivated carbon, respectively. The H2O concentration was reduced to 0.2%, 0.7%, 0.2%, 0.2%, and 0.3% for treating raw biogas\nwith 10 g of silica gel and Na2SO4 for runs R1, R2, R3, R4, and R5, respectively.Thus, given the successful contaminant elimination,\nthe combined absorption and adsorption process is a feasible system for biogas purification...
Narrow residence time distributions (RTDs) are desirable in many chemical engineering\nprocesses. However, when a system operates in the laminar flow regime, significant fluid\ndynamic dispersion takes place. This problem is often encountered in micro and millifluidic\ndevices. Exploiting the beneficial effects of secondary flow and chaotic advection, so-called\ncoiled flow inverters (CFIs) are a promising solution for the reduction of fluid dynamic dispersion.\nThese devices, however, have not been extensively used due to the lack of experimental\ndata and of correlations relating the design parameters and operating conditions to the\namount of axial dispersion. In this work, we investigated RTDs in micro and millifluidic\ndevices using step input injection and UVââ?¬â??vis inline spectroscopy for the detection of the\nconcentration of a tracer. Experiments were performed for different operating conditions\nand geometries. Helically coiled tubes (HCTs) were similarly characterized. Dispersion data\nwere expressed in terms of an axial dispersion coefficient and an empirical correlation was\nderived. The experimental results show that lower axial dispersion is achieved in CFIs as\ncompared to HCTs and straight tubes....
Common opal was dissolved in NaOH lyes in rotating autoclaves. The starting material\nwas characterized by X-ray diffraction and adsorption spectroscopy, thermal\nand chemical analysis, electron and atomic force microscopy. The opal proved to be\nan Opal-CT with a microstructure consisting of microcrystalline tridymite, traces of\nlow-quartz, and amorphous parts built up by random packings of size distributed\namorphous silica colloids. The dissolution conditions have been inspired by the\ntechnological process of hydrothermal water glass synthesis by dissolving silica.\nTemperature and time of the dissolution process as well as initial molar SiO2:Na2O\n(Rm) ratios of the starting materials were varied systematically. The particle size of\nthe samples was varied, too, but due to the nanoscopic microstructure without greater\nimpact on dissolution kinetics. The process products were analyzed chemically.\nAdditionally, some of them were characterized by X-ray diffraction, viscosimetry and\ndynamic light scattering. Already after short dissolution times, water glasses with\nquite high silica concentrations of up to 27 wt.% and SiO2:Na2O ratios of up to 3.7\nwere obtained. At longer dissolution times low-quartz and analcime precipitated and\nthe SiO2 contents were reduced to about 22 wt.% and Rm to about 2.7. The silica contents\nin equilibrium with low-quartz were almost independent on temperature....
This paper used a new approach of preparing poly-composites by covalent\nlinkage between the MWCNTââ?¬â?¢s by imine group. The Poly (Imine)/MWCNT\nComposite was synthesized by the solution blending method from reacted\namino multi-walled carbon nanotubes (MWCNT-NH2) with Terephthalaldehyde\n(TPAL). The obtained poly-composite was characterized by FT-IR,\nUV-Vis, XRD, TEM, SEM, TGA, DSC and DC electrical conductivity. The\nformation of Poly (Imine)/MWCNT composite was confirmed. The DC electrical\nconductivity of poly-composites was within the range 2.3 Ã?â?? 10âË?â??4 - 5.3 Ã?â??\n10âË?â??4 S/cm due to the interaction between the nanotubes....
Two dimensions (2D) C/SiC laminated composites is the material with isotropic\nproperties in laminated sheets, which is considered as a promising\nthermal skin for aircrafts. There are intense thermal flux and thermal impact\nat the local interference region during the flight of the aircrafts. Therefore,\nmastering ablation and mechanical properties of 2D C/SiC laminated composite\nunder extreme environments become the guild lines for the designs of the\nflight corridor and the aircraft security. This paper presents the experimental\nresults of the ablation and thermal impact of C/SiC composites under different\nthermal environments (thermal flux ~5 MW/m2), which were carried out\nwith the equipments of free-jets and conduct pipes. The effects on the ablation\nand mechanical properties of the C/SiC composites are studied, including gas\npressure, thermal temperature, and the rates of temperature increasing and\ndecreasing. The results show that the active oxidation and ablation behaviors\nof 2D C/SiC laminated composites under the thermal flux 5 MW/m2 consist\nwith that of theoretical simulations. The critical failure conditions of 2D\nC/SiC laminated composite is also provided for the enveloping designs of the\nwhole composites lightweight aircrafts....
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